The things I'd like to see gone are:
I agree 100% with your recommendations. Both of these menu items are not used daily by people, they are in fact used very seldom.
The ""Strech Icon" / "Restore Icon's Original Size" should go somewhere in a generic properties panel about size and whatnot, and the "Use Default Background" should just be added in the "background" panel. If the user needs to change his/her background, let her/him do all associated actions via the desktop properties panel.
The simpler the Nautilus menus, the better for all. Rgds,Eugenia